Double acting drawbench



A. J. GOOD DOUBLE ACTING DRAWBENCH June 28, 1966 '7 Sheets-Sheet 1 Filed Feb. 20, 1964 INVENTOR.

ALBE RT J. GOOD ATTORNEY June 28, 1966 A. J. GOOD 3,257,833

DOUBLE ACTING DRAWBENCH Filed Feb. 20, 1964 7 Sheets-Sheet 2 INVENTOR.

ALBERT J. GOOD ywf ATTOR NE 7 Sheets-Sheet 3 A. J. GOOD DOUBLE ACTING DRAWBENCH F l G. 4

n I HUMAN June 28, 1966 Filed Feb. 20, 1964 INVENTOR.

ALBERT J. soon ywwlf (4 ATTORNE F l G. 5

June 28, 1966 A. J. GOOD DOUBLE ACTING DRAWBENCH 7 Sheets-Sheet 4 Filed Feb. 20, 1964 32 FIG. 7

INVENTOR.

ALBERT J. GOOD FIG. 8

TORNEY June 28, 1966 A. J. GOOD 3,257,833

DOUBLE ACTING DRAWBENCH Filed Feb. 20, 1964 '7 Sheets-Sheet 5 INVENTOR ALBERT J. GOOD ATTORNEY June 28, 1966 A. J. GOOD 3,257,833

DOUBLE ACTING DRAWBENCH Filed Feb. 20, 1964 '7 Sheets-Sheet e N an FIG.

INVENTOR ALBERT J. GOOD ATTORNEY June 28, 1966 A. J. GOOD DOUBLE ACTING DRAWBENCH '7 Sheets-Sheet '7 Filed Feb. 20, 1964 mwmm mm EDGIOF Q2540; no.5 2300 304w INVENTOR.

ALBERT J. GOOD ATTORNEY United States Patent 3,257,833 I DOUBLE ACTING DRAWBENCH Albert J. Good, 354) Fairmount Ave. NE, Warren, Ohio Filed Feb. 20, 1964, Ser. No. 346,323

2 Claims. (Cl. 72278) This invention relates to apparatus for drawing metal tubes and bars and more particularly to such apparatus having a higher efliciency of production and requiring less factory floor space. Normally, such metal drawing apparatus utilizes a die stand and a bench projecting outwardly therefrom on which travels a draw carriage to draw the bars or tubes through the die or dies of the stand. With this arrangement the carriage is operative only during its outward travel and means must be provided to return the carriage back to the die stand for a new cycle of operation. During this return travel of the carriage the apparatus is, of course, unproductive, limiting the productive capacity of the equipment.

The primary object of the present invention is to increase the productive capacity of a metal drawbench without appreciably adding to the cost or complexity thereof, and this is accomplished in accordance with the principles .of the present invention by arranging the apparatus in such manner that a productive draw is accomplished in each direction of movement of the draw carriage. A die stand and suitableloading mechanism is provided for either end of the reciprocating path of travel of the draw carriage, the draw carriage itself is made double acting with grip bits on either end, and the draw chain which is utilized to apply the required heavy drawing forces is equipped with a reversing drive automatically controlled in a manner to be hereinafter described. Also, the frame for the bench itself is specially constructed to load workpieces, including tubes, from either end of the equipment and to discharge drawn workpieces regardless of the particular direction in which they have been drawn. Also, the discharge apparatus is arranged so that while workpieces of one size or specification is being drawn from one end of the bench workpieces of another size or specification may be processed from the other end of the bench.

A further and more specific object of the invention is the provision in a double-acting drawbench of the kind outlined above of an improved multiple control arrangement whereby the over-all apparatus is substantially automatic in its operation with the draw carriage shuttling back and forth and effecting a productive draw in either direction of its movement.

The above and other objects and advantages of the invention will become apparent upon consideration of the following specification and the accompanying drawing wherein there is disclosed a preferred embodiment of the invention.

In the drawing:

FIGURE 1 is a schematic plan view of a double-acting drawbench constructed in accordance with the principles of the invention, the view being broken at places to economize on illustration space;

FIGURE 2 is a schematic side elevation of the apparatus of FIGURE 1;

FIGURE 3 is a'transverse section taken along the III-III of FIGURE 2;

FIGURE 4 is a side elevation of a combined die stand and draw chain sprocket assembly utilized in the assembly of FIGURE 1;

FIGURE 5 is an end elevation of the apparatus of FIGURE 4 as viewed from the plane V-V of FIGURE 4, but omitting the die block which is shown in FIG- URE 4;

FIGURE 6 is a plan view, partly in section, of the double-ended draw carriage used in the assembly of FIG- URE 1;

line

FIGURE 7 is a longitudinal section through the carriage of FIGURE 6;

FIGURE 8 is an end elevation of the carriage of FIGURES 6 and 7;

FIGURE 9 is a transverse section taken along the line IXIX of FIGURE 2;

FIGURE 10 is a side elevation, partly in the apparatus shown in FIGURE 9;

FIGURE 11 is a plan view of an end portion of the workpiece loading mechanism utilized in the assembly of FIGURE 1;

FIGURE 12 is a side elevation, partly in section, of the apparatus shown in FIGURE 11; and

section, of

FIGURE 13 is a schematic representation of the draw motor control system utilized in the assembly of FIG- URES 1 and 2.

Referring first to FIGURES 1 thru 5, the drawbench of my invention comprises a pair of longitudinally spaced die stands 10A and 10B which are identical in design but reversed with respect to each other and of which stand 10A is shown more in detail in FIGURES 4 and 5. Thus, the stands are each comprised of a vertical slab having apertures 11 therethrough for the passage of the draw chains and an upwardly open socket 12 for the slideable reception of a die holder 13 (FIG. 4). As is well known in the metal drawing art, the die holders 13 are, in turn, formed with one or more sockets to receive one or more drawing'dies, depending on whether the apparatus is arranged for single or multiple draw. Also, in accordance with usual practice, these holders may be quickly removed and replaced in the die stands to replace worn dies or any changing over to other products.

In the construction of the particular drawbench illustrated, the stand 10A forms an end wall of a box-like housing 14 which projects outwardly of the stand 10A with respect to the longitudinal center of the apparatus. The stand 10B forms an inner end wall of a box-like housing 15. Journaled in the housing 14 is a shaft 16 to which is keyed a pair of drive sprockets 17 housed within the structure 14. Positioned within the housing 15 is a pair of idling sprockets 18 carried by a shaft 19 which is journaled in take-up blocks 20 slideably mounted in suitable ways in or on the housing 15. Shaft 16 which is the drive shaft of the apparatus is driven from a reversing direct current motor 21 through a speed reducer 22.

Entrained over the sprockets 17 and 18 is a pair of spaced parallel draw chains 23 which have breaks in their upper reaches for attachment to the opposite longitudinal ends of a double-ended draw carriage 24 shown more in detail in FIGURES 6 .thru 8. This carriage has four supporting wheels 25 which roll on a pair of spaced parallel longitudinal rails or tracks 26. Tracks 26 are, in turn, supported in openings through the transversely extending but longitudinally spaced frames 27 of which two are shown schematically in FIGURE 2 while one of which is shown in detail in end elevation in FIGURE 3. per reaches of the chains 23 slide on these rails 26 while the lower reaches of these chains slide on similar rails 28 passing through other openings 29 in the, frames 27. It should be obvious that when the motor 21 is energized in alternate directions the draw carriage 24 may be made to move from die stand 10A to die stand 10B and vice versa-shuttling back and forth to draw first lengths from one stand and then from the other stand, repeating the process so long as stock is fed into and through the dies held by the stand.

The double-ended draw carriage of this invention consists of a rigid frame 30 which mounts the wheels 25 and receives the ends of the draw chains 23, and each longitudinal end of this carriage is provided with a grip bit block, one of which is designated by reference numeral 31A 'while the other of which is designated by the refer- Pa'tented June 28,1966

The upence numeral 318. In accordance with usual practice, these blocks are formed with converging ways to slideably receive grip bits 32. Two of these bits are provided for each length to be drawn, and the particular drawbench illustrated is arranged for simultaneously drawing three lengths in each direction. Accordingly, each of the blocks 31A and 31B is fitted with three pairs of grip bits as illustrated. To operate the bits along their converging ways I provide for each of the bits a lever 33 which swings on a transverse rod 34 anchored in suitable supports 35 which are rigidly aflfixed to the frame 24. The lower end of each of the levers 33 is socketed in one or the other of the grip bits 32, as illustrated in FIGURE 7, in such manner that forward and reverse swinging movement of the levers will result in forward and reverse sliding movement of the grip bits. To retract the grip bits, I provide for each of the levers 33 a spring-pressed plunger 36 which are shown in FIGURE 7 and which abut against the levers 33 intermediate their ends. Opposing each of the plungers 36 is a fluid-actuated member 37, and it should be apparent that when the members 37 are actuated by the application of fiuid pressure, normally air, the grip bits will be slid outwardly into biting and gripping relation with the stock which enters the openings in the end walls of the blocks 31A and 31B.

While not particularly illustrated, the cylinders 37 at either end of the draw carriage are connected to a common conduit Which leads to an end fitting 38 rigidly carried on the carriage in predetermined position thereon. These fittings have alternate sliding connection with fittings 39 which are rigidly mounted on the die stands 14 and 15 in predetermined positions thereon. Air under pressure is supplied to the fittings 38 at proper times through supply conduits 40 and valves 41. These valves 41 are mechanically actuated by shoes 42 which are adjustably mounted on the die carriage 24, and the operation is such that as the opposite ends reach predetermined approaching positions with respect to the opposite die holders the valves will be actuated to supply compressed air to the fittings 39. By this time one of the fittings 38 will have slideably entered one of the fittings 39 so that cylinders 37 will be actuated to close the grip bits onto the workpieces which are projecting through the dies on the stand being approached. A pressure-responsive switch 43 is connected into each of the supply lines for the fittings 39 so that after sufiicient gripping force has been applied to the workpieces as determined by the buildup in pressure at switches 43 the draw motor 21 will be reversed to begin the drawing of the workpieces which are in the dies adjacent the draw carriage.

The details for the control of draw motor 21 are not an essential part of the present invention since such control may be devised by anyone skilled in the control art and, accordingly, the control is only schematically shown on the drawing at 44. This control, however includes suitable instrumentalities for speeding up and slowing down the motor 21 when operating in either direction and to initiate the actuation of such instrumentalities I provide the adjustable rocker switches 45 (FIGURE 13) which are actuated by an operator 46 mounted on the carriage 24. The control 44 further includes means for bringing the motor almost to a stop when operating in either direction and to thereafter apply only sufficient voltage V to the motor to exert enough torque to hold the carriage against one or the other of the die stands until the airoperated grip bits can be fully actuated. The initiating devices for the last named means are the limit switches 47 which are adjustably mounted on the bench and which are arranged for gate or one-way actuation by the operator 46.

Considering now the overall control for the draw motor 21 and referring particularly to FIGURES 1 and 13, it can be assumed in FIGURE 13 that the cariage 24 has just approached and contacted the die stand 14. At this time the plungers 36 (FIGURE 7) hold the grip bits open so that the latter can readily pass over the extremities of the pointed ends of the workpieces which have been loaded into the dies held by stand 14. At this time also the adjacent fitting 38 on carriage 24 has mated with the fitting 39 on stand 14 and pressure begins to build up in those cylinders 37 which actuate the grip bits which have just passed over the protruding ends of the workpieces. These grip bits now close onto the work and promptly the gripping pressure develops resulting in a sufficient increase in pressure in the line to fitting 39 to actuate switch 33. The latter initiates suitable instrumentalities in the control assembly 44 to reverse the energization of motor 21 and effect the initiation of outward movement of the carriage 24 at slow speed. The extremely heavy draw force or tension comes on slowly to firmly set the serrations of the grip bits onto the workpieces but shortly the operator 46 reaches the nearest rocker switch 45 which operates through control 44 to apply full voltage to the motor 21 and consequently maximum speed to the draw carriage.

The drawing operation continues until the tail ends of the workpieces are through the dies at which time the convulsive restriction of the workpieces cause them to jump free and clear of the grip bits, it being noted that at this time there is no air pressure on the cylinders 37 and the spring-pressed plungers 36 are tending to open the grip bits. At about the same time the operator 46 engages the opposite rocker switch 45 which, through control 44 decelerates the draw motor 21. At about the time a predetermined slower speed is reached the adjacent limit switch 47 is actuated (by operator 46) to bring the carriage almost to a stop While yet continuing to apply a predetermined holding torque voltage to insure that the draw carriage comes up against the die stand 15 without damage and to temporarily hold the draw carriage there. Thereafter the buildup of pressure at the switch 43 on die stand 15 reverses the energization of motor 21 and the above described sequence is effected during movement of the carriage 24 from stand 15 to stand 14.

The apparatus of the invention chosen for illustration is a triple-draw tube bench, and it will be understood by those familiar with the art that for some time it has been common practice to load tube benches by passing the open end of a pointed tube blank over a draw plug mounted on the end of an elongated mandrel. The blank and mandrel are advanced longitudinally to move the pointed end of the blank through the die where it may be engaged by the grip bits and to properly position the draw plug in the die. This general and accepted method can be used in the double-acting bench of my invention in the manner shown in the drawing and now to be described.

Referring first to FIGURES l, 2 and 3, I employ a trough or roller table 48 which is longitudinally and centrally disposed on top of the frames 27. This trough is adapted to receive the pointed tube blanks in lots of three (for triple draw), and it will be understood that alternate lots may be of different size or specification to correspond to the possibly different die and draw plug setups employed at opposite ends of the bench. A feed mechanism in the form of the upwardly swinging racks 49A and 49B actuated by cylinders 53A and 50B, respectively, is employed to assist in loading the trough or table 48 with blanks of alternate size or specification. Thus, the blank shown schematically at 51A on rack 49A may be subsequently loaded for being drawn through the dies on stand 14, for example, while the blanks shown at 51B on rack 49B may be subsequently loaded for drawing through the dies on stand 15. Of course, the pointed ends of the blanks supplied to rack 49A are directionally reversed with respect to the pointed ends of the blanks supplied to rack 4913. When it is desired to transfer blanks from one or the other of the racks onto the trough or table 48, the rack is tilted to horizontal position by its cylinder (50A or 503) and the appropriate number of blanks rolled off the rack by manual or automatic means, not shown herein.

In accordance with usual practice, the workpieces to be loaded are moved longitudinally from the trough or table 48 over the draw plugs and mandrels above mentioned, the plugs and the forward ends of the mandrels lying within guide tubes which are shown herein at 52. The mandrels are shown at 53. Since the loading mechanism at either end of the drawbench is identical, only one assembly will be described. Each of the loading assemblies comprises a rotatable affair having a longitudinally extending tie beam 54 carried within aplurality of longitudinally spacked disks 55 each rotatably supported on a stand 56. In the particular equipment illustrated, the guide tubes 52 and accompanying mandrels and plugs are arranged, as shown in FIGURE 9, in two spaced groups of three each for triple draw, the groups being interposable 0n rotational movement of the beam 54 and disks 55 to move a loaded group from alignment with the loading trough 48 into alignment with the adjacent drawing dies while the lower or empty group is moved from alignment with the dies up into alignment with the trough 48.

To rotate the assembly outlined above, one of the stands 56 is arranged with a gear motor 57 (FIGS. 9 and 10) and the disk 55 which is rotatably supported on this stand by means of rollers 58 is fitted with a peripheral sprocket over which is entrained a drive chain 59. As shown in FIGURE 9, the drive chain 59 is entrained over idler sprocket 60 and a drive sprocket 61 which is keyed onto the. gear motor 57.

The guide tubes 52 are bell mouth in the direction of the feed table 48 and the drawing dies and these tubes do not move longitudinally in the rotatable assembly, the mouths being properly positioned to have swinging clearance with respect to the adjacent end of the said trough or table and the draw dies. However, it will be readily understood by those familiar with the art that the mandrels 53 carrying the draw plugs, not shown, at their forward ends must have longitudinal sliding movement to permit the tips of the pointed ends of the blanks to be retracted sufficiently to permit them to swing into aligned positions with the dies after which the mandrels are moved forwardly to insert the pointed ends of the work- 62 which is mounted on the beam 64 and which has its piston rod connected to a header 63. The upper group of three mandrels is adjustably anchored to the header 63 at 64 and suitable solenoid operated valves 65 and 66 are employed to control the actuation of cylinder 62. It will be understood by those familiar with the art that these control valves are, in turn, controlled by a suitable sequencing circuit, not shown herein, provided to effect the automatic operation of the equipment. A similar cylinder 67 and a similar header 68 is provided toadjustably anchor and actuate longitudinally the lower group of three mandrels 53.

Referring now to the overall operation of the equipment above described, it should be first noted that while a group of tubes is being drawn through the dies at one end of the bench a second group of blanks has their pointed ends extending through the dies at the opposite end of the bench in readiness for being gripped and drawn during the next succeeding reverse traverse of the draw carriage. While the first mentioned group of tubes is being drawn the upper and empty guides and mandrels may be loaded from the table or trough 48 by means of a suitable pushing mechanism, not shown, or by driving the rollers if a roller table is used. Immediately upon completion of this first draw the lower mandrels and plugs are retracted and the loading assembly rotated to bring the newly loaded guide tubes and mandrels into alignment with the dies preparatory to the return of the draw carriage to this end of the bench. The loading mechanism at the opposite end of the bench is similarly manipulated so that the drawing proceeds apace,

first from one end of the bench and then from the other end of the bench, rapidly repeating the sequence to rapidly produce large tonnages of drawn products with a minimum amount of equipment. 7

Referring back again to FIGURE 3, it will be noted that the frames 27 are each provided with downwardly hand slots 69 which lead to a pair of side-by-side bins 70 and 71. A swingable gate 72 selectively exposes the bins 70, 71 to the products sliding or rolling down the slots 69 for proper batching when products of different size or specification are being drawn from opposite ends of the bench.

It should now be apparent that I have provided improved drawbench apparatus which accomplishes the objects initially set out above. By doubling the use of the principal and more expensive parts of the equipment such as the drive, chain, bench proper and carriage, the productive capacity of the equipment is vastly increased, enabling the drawing plant to operate much more economically. The invention eliminates the requirement for any separate carriage return mechanism and the power required therefor, and also materially reduces the factory floor space required. Another advantage of the arrangement of the invention is that the use of two opposed die stands stabilizes the bench structure and allows the longitudinal members of the long expanse of the bench to be made rather light and inexpensively, all in contrast to conventional drawbenches wherein the long expanse of the bench must in itself possess su'flicient columnar strength to oppose the heavy tensive forces in the draw chain.

While I have, for illustration purposes, chosen a multiple-draw tube bench it should be readily apparent to those skilled in the art that the principles of the invention are equally applicable to single-draw tube benches and to single and multiple-draw bar benches. Also, various other changes may be made in the design and construction of the equipment without departing from the spirit or scope of the invention, and reference should accordingly be had to the appended claims in determining the scope of the invention.

I claim:

1. Apparatus for drawing elongated metal shapes comprising a pair of longitudinally spaced die stands facing each other and each having at least one drawing die, a benchextending longitudinally between said stands and movably supporting a draw carriage said bench comprising a plurality of transversely extending but longitudinally spaced C-shaped frames each having a downwardly inclined slot for the ejection of drawn workpieces and having a transversely elongated opening for the passage of said carriage and the side edges of said slots constituting supports for longitudinally extending rails on which said carriage is movably supported, a grip bit assembly at either longitudinal end of said carriage and operative to engage workpieces extending through said dies, a pair of transversely spaced sprockets associated with each of said stands each operative to entrain the end loops of a draw. chain, a pair of draw chains entrained over said sprockets and connected to said carriage for moving the same back and forth along said bench, said sprockets and chains being generally laterally aligned with said rails and said frames having openings below the slots in the carriage on said bench and be discharged after drawing 7 downwardly and outwardly through said slots.

2. Apparatus according to claim 1 further including a control for said reversing drive comprising unidirectional limit switches mounted along said bench and an Y S actuator therefor mounted on said carriage, said control 2,536,637 1/1951 Garwig 205-3 being operative to slow down the carriage as the same 2,717,072 9/1955 Andrews 2053 approaches either end of its stroke and t0 the eaf e 2,837,206 6/1958 McIlvried 2053 yieldingly retain said carriage in cont ct with t j 2,845,171 7 1953 Heym 205-3 Cent die Stand- 5 2,919,016 12/1959 Turner 205-22 References Cited by the Examiner 30876O4 4/1963 Coan 20524 UNITED STATE ATE T CHARLES W. LANHAM, Primary Examiner. 2,446,438 8/1948 Strock 2053 H. D. HOINKES, Assistant Examiner.

2,472,231 6/1949 Rodder 205 7 10 

1. APPARATUS FOR DRAWING ELONGATED METAL SHAPES COMPRISING A PAIR OF LONGITUDINALLY SPACED DIE STANDS FACING EACH OTHER AND EACH HAVING AT LEAST ONE DRAWING DIE, A BENCH EXTENDING LONGITUDINALLY BETWEEN SAID STANDS AND MOVABLY SUPPORTING A DRAW CARRIAGE SAID BENCH COMPRISING A PLURALITY OF TRANSVERSELY EXTENDING BUT LONGITUDINALLY SPACED C-SHAPED FRAMES EACH HAVING A DOWNWARDLY INCLINED SLOT FOR THE EJECTION OF DRAWN WORKPIECES AND HAVING A TRANSVERSELY ELONGATED OPENING FOR THE PASSAGE OF SAID CARRIAGE AND THE SIDE EDGES OF SAID SLOTS CONSTITUTING SUPPORTS FOR LONGITUDINALLY EXTENDING RAILS ON WHICH SAID CARRIAGE IS MOVABLY SUPPORTED, A GRIP BIT ASSEMBLY AT EITHER LONGITUDINAL END OF SAID CARRIAGE AND OPERATIVE TO ENGAGE WORKPIECES EXTENDING THROUGH SAID DIES, A PAIR OF TRANSVERSELY SPACED SPROCKETS ASSOCIATED WITH EACH OF SAID STANDS EACH OPERATIVE TO ENTRAIN THE END LOOPS OF A DRAW CHAIN, A PAIR OF DRAW CHAINS ENTRAINED OVER SAID SPROCKETS AND CONNECTED TO SAID CARRIAGE FOR MOVING THE SAME BACK AND FORTH ALONG SAID BENCH, SAID SPROCKETS AND CHAINS BEING GENERALLY LATERALLY ALIGNED WITH SAID RAILS AND SAID FRAMES HAVING OPENINGS BELOW THE SLOTS IN THE FRAMES AND GENERALLY VERTICALLY BELOW SAID RAILS TO MOVABLY RECEIVE THE LOWER LONGITUDINAL REACHES OF SAID CHAINS, AND A REVERSING DRIVE COUPLED TO THE SPROCKETS ON ONE OF THE STANDS FOR DRIVING THE SAME IN OPPOSITE DIRECTIONS, THE GENERAL ARRANGMENT OF THE APPARATUS BEING SUCH THAT ELONATED WORKPIECES MAY BE DRAWN BY SAID CARRIAGE THROUGH SAID DIES IN EITHER DIRECTION OF MOVEMENT OF SAID CARRIAGE ON SAID BENCH AND BE DISCHARGED AFTER DRAWING DOWNWARDLY AND OUTWARDLY THROUGH SAID SLOTS. 